Patent application EP-A-1 850 094 describes a sensor that detects the rotation of a rotating shaft and comprises an annular member adapted for coupling by socketing on the mentioned shaft, said annular member being provided with a notched configuration coupling with a pinion to which it transmits the rotation of an angular position sensing device. The sensor comprises a first cavity with a through hole housing the mentioned annular member and an adjacent second cavity in which the mentioned sensing device is arranged. In this construction an exact positioning of the annular member in relation to is the mentioned pinion must be assured in order to guarantee the operation.
U.S. Pat. No. 7,378,848 describes an angular position sensor with a through hole and two non-symmetrical polar pieces associated with a magnetic field sensor. This sensor uses a magnetic ring arranged to be coaxially coupled to a rotating shaft which, together with said magnetic ring, is inserted through a cavity of a casing of the sensor. The sensor comprises two polar pieces which extend at least partially around the magnetic ring. The features of this sensor and the number of components involve considerable complexity and the need for very precise adjustments.
U.S. Pat. No. 6,188,216 describes a non-contacting angular position sensor of a rotating shaft, which comprises a casing with a cavity housing a polar assembly formed by two semicircular magnets fixed to a bearing body which is fixed directly to the shaft and a magnetic field sensor. The features of this sensor impose the use of two magnets separated at a very precise certain distance, coupled on the bearing body, which involves constructive limitations.